Some Aspects of Reaction of 6-Aminouracil and 6-Amino-2-Thiouracil with α,β-Unsaturated Ketones

Abstract

A number of 5,7-diaryl-5,8-dihydropyrido[2,3-d]pyrimidines and 5,7-diarylpyrido[2,3-d]- pyrimidines were obtained by the reaction of 6-aminouracil derivatives with α,β-unsaturated ketones. Basic catalysts decrease yields of the dihydro derivatives whereas acids increase it. In the reactions of ketones containing the dimethylamino group, elimination of the aryl substituent from position 5 of the pyridopyrimidine system was observed. Some aspects of oxidation of 5,8-dihydropyrido[2,3-d]pyrimidines and synthesis of pyrido[2,3-d]pyrimidines were also investigated.